The present invention relates to treatment of waste sulfurous acids coming from plants in which various products are processed, in particular raw materials that contain titanium oxide and used for producing industrial TiO.sub.2.
In the above application as well as in most of those related with sulfurous acids, great amounts of acid effluents must be evacuated or treated.
A re-treatment generally involves concentrating the diluted acids and separating the polluting elements such as fluorides, heavy metal oxides, aluminous residues, etc.
The above treatments are very costly and not satisfactory since the diluted acids can not be easily concentrated and can not be re-cycled a great number of times, and since there is still the problem of removing the separated polluting materials.